charging of battery

[martincbx]

Hi all,
I am from Germany and new to this forum.
I bought my M-715 last year from Nevada, got it shipped to Europe and now I finally have on the road. There is less than 5 original M-715 on the road in Germany, can you believe ?

But I have an electrical problem.
When I start the motor, it runs on battery. As soon as I disconnect the battery cable the engine dies.
But if I do this about 5 times, then, all over sudden, the generator works, the engine runs without battery and the relating gauge shows 'green'.

It is like I have to initialize the charging system by playing with the battery cable before it starts working.

Does anybody have an idea where the problem could be and where to look at ? fyi it has the 24V system and generator.

Many thanks for your help.
best 'M-715'-regards
Rainer

[amphi]

Greetings martincbx and welcome to the zone.

My first thought is the brushes might be worn down or sticking.

Next time it does this, try tapping lightly on the alternator with a hammer. Sometimes this shock will cause lifted brushes to make contact and it will begin charging. If this works, repair or replace the brushes.

There is a detailed procedure for the 100 amp alternator documented in the TM 9-2320-244-20 Organizational Maintenance Manual found under the Online Maintenance Manuals at the top of this page.

(2) Check field resistance. Set ohmmeter selector to R x 1 scale. Connect ohmmeter leads to pins D and E of alternator receptacle. Meter should read less than 4 ohms. To assure that brushes are contacting the slip rings, and rings are clean throughout all points of contact, remove the fan belts from the alternator and rotate the rotor at least five times by hand. Ohmmeter reading should be constant and remain at approximately 4 ohms or less. Install belts and adjust.

http://www.m715zone.com/vb/view.php?pg=20chap3-4


Hope this helps.

[Bushytails]

Two possibilities... The most likely is that the alternator is due for a tuneup/rebuild. Either the brushes are worn and sticking, or the regulator has become marginal.

The other would be that the ignition switch is failing, and by starting and stopping it enough times, you get one time where it makes contact and turns the alternator on. You can test this with a test light on the small, unpluggable wire going to the top of the alternator.

--Bushytails

[Kaiserjeeps]

Greetings and welcome!!! How much did it cost to ship your truck home?

[martincbx]

thanks to everybody. I will try and report.
I am running my own shipping business, so for me it is very easy to get cars and things shipped to Europe. The transport from Nevada to Houston, the port of shipment was almost the same cost than shipping to Europe. Altogether from Reno to my place which is in the middle of West Germany was about $ 2.200.

[MarknessMonster]

Altogether from Reno to my place which is in the middle of West Germany was about $ 2.200.

Some folks here have probably paid $2,200.00 just to get their trucks half way across the U.S.A., and you managed to ship a truck overseas for less than 30 cents a mile. That's a pretty economical transportation service! What was the length of time to receive the Nevada, USA truck in Germany?

3

[martincbx]

transport from Reno, Nevada to Houston was three days, then 10 days at the port for clearing the documents, stowing the container etc. another three weeks transit from the port of Houston to the port of Rotterdam in the Netherlands. This is only about 150 miles from my home. So I went there myself and picked up the truck and trailered it home.
Total transit time was 6-7 weeks.

[martincbx]

I had checked the wiring and everything but still the alternator doesn't work.
So I took it out today and opened it but I can't see anything wrong. I ordered a rectifier kit from memphis Equip which basically contains the rear half of the alternator. I hope this helps.

You know sometimes you just have to wonder what some people do to their cars. There was a 12 V alternator beside the 24 V alt installed. A terrible lot of wiring, some double, some cut and some of them loose at both ends.
I took out everything that obviously had no use, I dismantled the 12 V alternator and its wiring. But still under the dash a lot of strange wiring remains. I will have to take care of that in a next step.

I can imagine that some of this strange wiring caused a problem and might have destroyed something in the alternator. So I hope the rectifier kit will help to solve the problem.
The alternator is correctly connected to the foot switch and from there to the battery.
Nothing else in between, so I imagine that the problem of not charging can only result from the alternator.
I will let you know when the kit has arrived and is installed.

One thing I have to say.
This forum is really great and only by reading I have learnt a lot about my M-715.
One day I will come over and join a meetuing or field exercise. I'd love to meet with some of you guys. Thank you.

[brute4c]

Your alternator should have 3 wires...if this is a stock alternator...

1. Ground wire from altenator to mounting bracket...large gauge wire.

2. Wire #5 from the foot starter swith, battey side to the alternator, large gauge wire.

3. Wire #468 OR #568, it seems to vary...this is the wire that excites the field to start charging. This is a small wire that goes under the little removeable metal cover on top with the big #5 wire. The wire runs to a factory wire splice, where it has 2 wires coming out the oter side. One of these wires runs to the On/Off switch. When the switch is On and the alternator is turning, this wire sends a bit of power to the alternator to shart the charging process.
The other wire that comes from that splice goes to a special splice and seperates into 4 wires that are the power wires to the gauges. This is called the Spider Harness.

Might help you track something down...

I spent a couple years in Germany in the USAF...hope to come back someday...I was about straight south of you at Flugplatz Hahn in the Hunsruck...now closed...

[randygar]

If I were to guess, the second alternator mounted in parallel was to make up for the original one not working!

Did you check for power to the smaller wire from the ignition switch as I suggested above?

If it's got a lot of redneck wiring, your best bet might be to rip it out and start over... that's what I did. Poorly ran wires pinched and cut on metal edges, crimps that fell apart when you touched them, a 12->6V converter used as a 24->12V converter (and melted, of course), etc, etc... Spent a few hours removing every trace of the last person's wiring job, then re-wired everything properly!

--Randy